Want more stopping power

[jfheath]

Excessive use of grease in the wheel bearings. Check the disc surface see if it is coated with anything.

I've owned the ABS and the non ABS 1100. The ABS version has far superior brakes.
Honda pads are much better. My ST1100 non ABS was the only bike to which I fitted EBC HH pads. I was not impressed.
Have a good ride in the rain on the road up to Grassington and use the brakes a lot. You won't have to wait long - there was a big downpour in Skipton about 10 this morning. There will be more tomorrow. It steam cleans and sand blasts the pads and discs all in one go. After half an hour they are as sharp as they can be. Your bike will be filthy though.

Or you can pop along the A65 one day.

 

[dwalby]

The ABS version has far superior brakes.

I rode the ABS version first, and I agree it is much easier to hop on and ride and get excellent braking by doing nothing more than pulling the lever. But, I think with experience and practice using both brakes effectively the non-ABS version isn't that far behind, but it takes a lot more work and practice.

 

[Ron]

I've never ridden a non-ABS ST so I don't know. But after hearing the same story from many people, there must be some truth in it. The force exerted on the rotor is a direct result of the force put on the MC lever. But with the smaller bore MC, you're letting the hydraulics do the "heavy lifting". We don't all have manly He-Man hands. For ~ $50 (ebay MC), some brake fluid and a couple hours work, I'd give it a whirl. It is a direct interchange. If you don't like it, put the original ST master cylinder back on and sell the MC.

Brake: www.st-owners.com/forums/threads/brake-master-cylinder-swap.168536/

As I said before, the clutch mod (same concept) works great!

Clutch: www.st-owners.com/forums/threads/clutch-master-cylinder-swap.167869/

 

[OkieRider]

Delete the link and switch to dual stainless lines up front

 

[ST Gui]

I've just reread Beemer's clutch mod thread. I laughed a lot. When advised systems are matched by the designers and changes may result in a system that simply doesn’t work properly he replied "That risk follows those of us around who cannot leave well enough alone. I"m familiar with it".

When acknowledged his mission was cool, he replied "There is not much distance between cool and fool. I'll fess up if it flops".

And it did not. A very nice mod indeed.

 

[wjbertrand]

What pads are in there now? I had a wooden feel with my old '93 ST ABS ( the pre '96 ABS models had the same calipers and non-linked system as the standard models) using aftermarket pads, Ferrodo and EBC. Went back to OEM and it was much better in feel. No real reduction in effort but good enough to activate the front ABS. With the aftermarket pads it was really hard to get to that point. The Ferrodos in particular I found downright scary in the rain.

 

[dwalby]

Hey, it just occurred to me that a few years ago I had an intermittent issue with my brake lever feel. Most of the time it was normal, but every so often the feel would change to what might be accurately described as a 'wooden' response, and then it would go back to normal again fairly soon after. I thought the MC was going bad and I'd need to rebuild it, until I read someone post on this forum that they fixed that issue by lubing the linkage between the brake lever and the MC. I can't remember exactly what I did, because it was so simple and took so little time it never registered, but I think I just took a can of spray lube and pushed the straw in past the rubber cover between the lever and the MC pushrod and sprayed. Or I may have removed the rubber cover and sprayed it directly, but you get the general idea. After doing that I've never had that feel return again for several years now.

 

[RobbieAG]

When I owned both a non ABS 1100 and a non ABS 1300, there was quite an adjustment going from one to the other. I now own the 1300 and a much smaller/lighter 2017 SV650 and still have to adjust when switching bikes (FYI, the SV is more like the 1100 than the 1300 as far as brake feel). Once you mentally adjust though, the brakes on the 1100 (and SV) are fine. You can easily lock up the wheel without that much effort, so what more do you need?

 

[Pete68]

Excessive use of grease in the wheel bearings. Check the disc surface see if it is coated with anything.

I've owned the ABS and the non ABS 1100. The ABS version has far superior brakes.
Honda pads are much better. My ST1100 non ABS was the only bike to which I fitted EBC HH pads. I was not impressed.
Have a good ride in the rain on the road up to Grassington and use the brakes a lot. You won't have to wait long - there was a big downpour in Skipton about 10 this morning. There will be more tomorrow. It steam cleans and sand blasts the pads and discs all in one go. After half an hour they are as sharp as they can be. Your bike will be filthy though.

Or you can pop along the A65 one day.

I guess you know the skipton area..Am Just down the road 5 miles south out at crosshills ...Great idea for the rain clean..It has Ebc pads in ,Fa142/196 BTW.

 

[tnbill]

I did the cbr 600F3 front brake master cylinder change yesterday looking to improve the brakes. My stock master was a 14 MM bore and this is 13MM so not a big change there. I did a rebuild and lever swap as the cbr had a polished lever vs black. It was pretty much a bolt on but i did have to remove the cast on hose stop as it puts the hose in a different rotation. Was it worth it? For less than $100 it was and i did get an improvement it stopping power.

 

[Larry Fine]

So, a smaller-bore MC means more lever travel, but less lever pressure required, right?

 

[TerryS]

Absolutely right. It's a leverage thing, think about using a longer lever (the smaller diameter MC) moving further vs a shorter lever (bigger bore MC) moving a smaller distance. I personally swapped a 1999 VFR800F M/C (which I just happened to have handy) onto my 1990 ST11, so a 12.7mm M/C replacing a 14.0mm standard M/C. I also installed braided lines and EBC HH pads. This changed the brakes from wooden to having a nice amount of grab. Any added mushiness from the smaller MC was offset by the braided lines.

 

[dwalby]

Absolutely right. It's a leverage thing, think about using a longer lever (the smaller diameter MC) moving further vs a shorter lever (bigger bore MC) moving a smaller distance. I personally swapped a 1999 VFR800F M/C (which I just happened to have handy) onto my 1990 ST11, so a 12.7mm M/C replacing a 14.0mm standard M/C. I also installed braided lines and EBC HH pads. This changed the brakes from wooden to having a nice amount of grab. Any added mushiness from the smaller MC was offset by the braided lines.

I was a bit bored tonight and gave this a little bit too much thought, which I have written below. If you have the time and inclination, give it a read and interject your own comments.


There are two variables potentially in play if you swap out the entire m/c. One is the size of the m/c bore, the other is the leverage between the brake lever and the m/c plunger. Since I've never done a swap, I can't say if most/all motorcycle m/c have the same brake lever to plunger leverage ratios or not. For the sake of argument, let's say they're the same for now.

Using a little math to describe the differences, let's say the original m/c has a bore area of 0.3 in2, and the new m/c is 0.25 in2. If a given amount of brake lever pressure develops say 10lbs of force at the m/c plunger, then that's applying a pressure of 40psi for the new m/c and 33.33psi for the original. Pressure is conserved inside the system, so that same pressure is applied at the brake pads.

If the caliper area is 2.0 in2, then the new m/c will be applying 80 lbs of force at the caliper, while the original will apply 66.67 lbs. The hydraulic leverage is 0.125:1 for the new m/c and 0.150:1 for the original, so if the brake lever creates 0.5" travel at the m/c plunger, the brake pads will travel by 0.0625" with the new m/c and 0.0750" with the original. In both cases, the lever applies 5.0 in-lb of work to the m/c, and that same amount of work is applied at the brake pads, work is conserved.

Now let's say that the first 0.0625" is what is required just to get the pads to contact the rotor before the real braking starts, and the effective force on the lever up to that point is essentially zero because there's no resistance from the pads. The lever will need to be moved a bit further on the new m/c compared to the original to get to that point. Also, the math shown in the previous paragraph shows that for any given force applied at the lever, the force applied to the pads is higher with the new m/c by the ratio of 80/66.67. Once the pads are firmly pressed against the rotor, neither the pads nor the rotors compress, so the movement essentially stops at that point and the braking forces are transferred directly from the lever to the pads. As more force is applied to the brake lever, the new m/c will provide a proportionally higher force to the brake pads compared to the original m/c. This will result in greater overall braking force, but may make the braking force a bit more 'grabby' than the original m/c because the braking force at the pads will increase from zero to lockup with less pressure applied at the lever.

So now to my question. I'd thought before that the smaller diameter m/c would provide a bit better 'feel' to the braking because of the increased leverage factor requiring more lever travel for a given amount of brake pad travel. But, after drawing it out above, it would appear that the opposite is true, the higher force leverage makes the applied braking force curve steeper, which would seem to make it have less 'feel', although providing greater overall power for a given force at the lever.

To adjust the force curve so its less steep, the leverage between the brake lever and the m/c plunger could be changed, but then that would just bring us back towards the same overall power ratio as the original m/c, and it looks like a TANSTAAFL situation. You can have more power, or more feel, but not both, you give up some of one for some of the other.

But, this got me thinking about how every bike I've owned since the late '80s I've swapped out the rubber brake lines for SS braided ones, and the braking 'feel' improved on every bike. The only difference with the braided lines is with less brake line expansion/swelling going on during braking, the lever force is more directly applied to the brake pads because there is less loss of pressure due to line expansion. That would mean for a given amount of pressure at the lever, more pressure is applied at the caliper with the braided lines compared to the stock rubber ones, and the force curve would be slightly steeper with the braided lines. So, from that I have to conclude that better braking 'feel' is probably more a result of greater pad pressure for a given lever input, and not due to a more gradual force curve.

Since you changed all three at once, lines, pads, and m/c, its probably hard to sort out the individual contribution of each component, but someone else on the forum had also done the m/c swap with a smaller diameter and also claimed it gave better power/feel.

 

[tnbill]

there was a chart put up by vintage brake the had MC bore vs caliper piston ratio. his thoughts was the be in the 27 to 1 range. I did not look at the caliper piston size so I am not sure where I am at BUT it did give an improvement in stopping vs lever pressure be a small change in piston size. from my understanding the factors in brakes is hydraulic pressure, be it a change in MC bore, caliper piston size and number of calipers or the lever itself. rotor diameter which changes how leverage the wheel has over the brake and swept area of the pads. on my old norton I have sleeved the master from 5/8 to 13MM to give more pressure. SS brake line and a rotor change from 10 inch to 330 MM but I still have the stock caliper with tiny silver dollar size pads so no increase in swept area BUT it is a far better brake the stock.